Scotch broom (Cytisus scoparius), also referred to as broom, is a perennial woody plant native to Europe. The species was introduced as a garden ornamental to North America and now is common across western Canada and California. Scotch broom plants grow up to 10 feet tall with sharply angled branches off the main stem, trifoliate leaves, and bright yellow small flowers. Scotch broom spreads quickly and aggressively at the expense of other plants and trees and is often considered a pest.

Both the flower and herb of scotch broom have been used medicinally. There is very little available scientific evidence about the efficacy or safety of this plant, and most conclusions come from knowledge of its constituents or from traditional use. There is particular concern about the potential toxicity of scotch broom due to the presence of small amounts of the toxic alkaloids sparteine and isosparteine, which are found in both the flowers and herb (above-ground parts). Sparteine has known effects on the electrical conductivity of heart muscle and can potentially cause dangerous heart rhythms or interact with cardiac drugs. Sparteine is also known to cause uterine contractions and should be avoided during pregnancy. Life-threatening adverse effects have been associated with sparteine and therefore scotch broom should be used only under strict medical supervision.

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

GRADE *

Scotch broom herb has been taken by mouth traditionally for a variety of conditions related to the heart or blood circulation. These include abnormal heart rhythms (arrhythmias), fast heart rate (tachycardia), swelling in the legs (peripheral edema), water in the lungs (pulmonary edema, congestive heart failure), and low blood pressure (hypotension).

Scotch broom flower has been taken by mouth traditionally for tachycardia and to reduce leg swelling by increasing urination (diuretic), as well as for damage to the heart muscle (cardiomyopathy) and for poor circulation.

There is a scientific basis for some of these uses, due to the presence in scotch broom herb and flower of small amounts of the alkaloid sparteine. Sparteine may affect the electrical conductivity of heart muscle (similar to type 1A antiarrhythmic drugs such as quinidine). However, there is limited evidence in humans and it is not clear if sparteine found in the plant form has clinically meaningful effects. These potential properties of scotch broom may be dangerous in individuals with heart disease or taking cardiac medications. People with cardiovascular disorders should be evaluated and supervised by a licensed healthcare professional.

C

Scotch broom preparations, particularly those made from the flower, have been used traditionally as diuretics (to increase urination). Diuretic effects have been attributed by some to the constituent scoparin or scoparoside. There is insufficient scientific evidence at this time to form clear conclusions about safety or efficacy in humans.

C

Scotch broom herb has been used historically to stimulate uterine contractions at birth and to reduce post-partum hemorrhage (bleeding after birth). There is a scientific basis of this use, due to the presence in scotch broom of small amounts of the alkaloid sparteine, which was studied and used through the 1970s as an oxytocic drug (to induce labor). This use was discontinued due to serious toxicities associated with sparteine. Currently, other drugs such as oxytocin (Pitocin®) are used for this purpose. The safety and efficacy of scotch broom preparations in labor are not well studied or established. Women who may require labor induction should be evaluated and supervised by a physician.

C

* Key to grades

A: Strong scientific evidence for this useB: Good scientific evidence for this useC: Unclear scientific evidence for this useD: Fair scientific evidence for this use (it may not work)F: Strong scientific evidence against this use (it likley does not work)

Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.

It is not clear what dose(s) of scotch broom are safe or effective for any medical condition, and use should only be under medical supervision. Storage of the flower or herb should be in a cool, dry location.

A juice has been made by pressing the bruised, fresh tops and adding one-third volume alcohol, allowing it to sit for seven days, followed by filtration, and taken daily as needed. An infusion has been made by adding 1 ounce of dried tops to a pint of boiling water (or 1 teaspoon in 200 milliliters boiling water) and taken as a cup-full once or twice daily as needed.

As a tea, 1-2 grams (1 level teaspoon) of herb can be steeped in 150-200 milliters of boiling water, then strained after 5-10 minutes and taken as a cup-full, up to three times daily as needed. As a decoction, 1-2 grams of herb have been used in preparations. As a liquid extract, a 1:1 preparation in 25% ethanol (v/v) has been prepared and taken as 1-2 milliliters as needed. As a tincture, a 1:5 preparation in 45% ethanol (v/v) has been taken at a dose of 0.5-2 milliliters daily. The herb may also be available as an aqueous-ethanol preparation (1:1:5) or as an aqueous essential oil extract.

Children (younger than 18 years)

Avoid due to potentially life-threatening toxicity.

Safety
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.

Allergy

Avoid if hypersensitive to scotch broom or any of its constituents, including sparteine.

Side Effects and Warnings

Scotch broom contains sparteine and alkaloid with anti-arrhythmic properties and potential cardiac toxicity (reported as similar to class 1A antiarrhythmics such as quinidine). Blood pressure changes and circulatory collapse may occur with large doses taken in any form, including by mouth or smoked in cigarettes. There is a possibility of abnormal heart rhythms, heart attack, and worsening of heart failure. Therefore, use of this herb should only be under medical supervision and extreme caution is warranted in individuals with a history of heart disease, abnormal heart rhythms, high blood pressure, or those taking heart medications.

Topical (skin) use may cause irritation due to the presence of saponins.

Pregnancy and Breastfeeding

Scotch broom should be avoided during pregnancy. Scotch broom contains the alkaloid sparteine, which is known to cause uterine contractions, and carries a risk of inducing abortion (abortifacient properties).

Scotch broom should be avoided during breastfeeding due to insufficient evidence and a hypothetical risk of serious toxicity.

Scotch broom contains the alkaloid sparteine, which may affect cardiac conductivity. Use in individuals taking other heart medications that affect heart rhythm such as digoxin, beta-blockers, calcium channel blockers, or other antiarrhythmics may be hazardous and should be avoided unless under strict medical supervision.

Scotch broom contains the alkaloid sparteine, which can potentially increase (or decrease) blood pressure. Use is not recommended in patients with a history of abnormal blood pressure or taking blood pressure medications.

Scotch broom contains small amounts of tyramine, which can lead to hypertensive crisis in individuals taking MAOI drugs. Therefore, this combination should be avoided. MAOI drugs include Isocarboxazid (Marplan®), phenelzine (Nardil®), and tranylcypromine (Parnate®).

Interactions with Herbs and Dietary Supplements

Scotch broom contains the alkaloid sparteine, which can potentially decrease or increase blood pressure. Use is not recommended in patients with a history of abnormal blood pressure or taking agents with significant effects on blood pressure.

Herbs with potential effects on heart rhythm similar to digoxin may pose a risk of heart block or abnormal cardiac rhythms when used with scotch broom, which contains the cardioactive constituent sparteine.

Scotch broom contains the toxic alkaloid sparteine, which is metabolized (broken down) by the liver's cytochrome P450 2D6 (CYP2D6) isoenzyme system. Therefore, herbs that inhibit CYP2D6 can increase the potential toxicity of scotch broom, including a risk of life-threatening adverse events such as cardiovascular collapse.

Scotch broom contains small amounts of tyramine, which can lead to hypertensive crisis in individuals taking MAOI agents. Therefore, this combination should be avoided.

The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.